View source for Ball-and-socket joint

{{short description|Ball-shaped surface of one rounded bone fits into the cup-like depression of another bone}}
{{About|bone joints|ground glass joints|Ground glass joint#Ball-and-socket joints|similar mechanical joints|ball joint}}
{{Infobox anatomy
| Name        = Ball and socket joint
| Image       = Gelenke Zeichnung01.jpg
| Caption     = '''1''': Ball and socket joint; '''2''': [[Condyloid joint]] (Ellipsoid); '''3''': [[Saddle joint]]; '''4''' [[Hinge joint]]; '''5''': [[Pivot joint]];
| Image2      = Gray327.png
| Caption2    = Capsule of [[shoulder]]-joint (distended). Anterior aspect.
| System      =
| Precursor   =
}}

The '''ball-and-socket joint''' (or '''spheroid joint''') is a type of [[synovial joint]] in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes, which have one common center. This enables the joint to move in many directions.

An '''enarthrosis''' is a special kind of spheroidal joint in which the socket covers the sphere beyond its equator.<ref name="Platzer2008p28">Platzer, Werner (2008) ''Color Atlas of Human Anatomy'', Volume 1, [https://books.google.com/books?id=T9bb4T422j8C&pg=PA28 p.28]</ref>

==Examples of joints==
Examples of this form of articulation are found in the [[hip]], where the round [[femoral head|head of the femur]] (ball) rests in the cup-like [[acetabulum]] (socket) of the [[pelvis]]; and in the [[shoulder joint]], where the rounded [[upper extremity of humerus|upper extremity of the humerus]] (ball) rests in the cup-like [[glenoid cavity|glenoid fossa]] (socket) of the [[scapula|shoulder blade]].<ref>And the phalanges (toes, fingers). [http://anatomy.med.umich.edu/modules/joints_module/joints_20.html Introduction to Joints: Synovial Joints - Ball and Socket Joints] {{webarchive|url=https://web.archive.org/web/20110720091324/http://anatomy.med.umich.edu/modules/joints_module/joints_20.html |date=2011-07-20 }}</ref> (The shoulder also includes a [[sternoclavicular joint]].)

== Ball and Socket Joint Animation ==
[[File:Ball Socket.webm|none|thumb|Ball and Socket joint animation]]

== Diagrams ==
<gallery>
Kugelgelenk.jpg|Hip
Gray327.png|Shoulder
Ball and Socket Joint (Hip joint).svg|Details of hip joint. {{ordered list |Femur |Femoral Neck |Femoral Head |Acetabulum |Acetabular labrum |Pelvis}}
</gallery>

==References==
{{Gray's}}
{{Reflist}}

==External links==
*{{Commons category-inline|Spherical joints}}
*{{Wiktionary-inline|ball-and-socket joint}}

{{Joints}}
{{Portal bar|Anatomy}}
{{Authority control}}

[[Category:Joints]]